Cureus. 2022 Jan 22;14(1):e21485. doi: 10.7759/cureus.21485. eCollection 2022 Jan.
Background With the rapid spread of coronavirus disease 2019 (COVID-19), most countries took extreme measures to control the disease. Equitable access to safe and effective vaccines is critical to ending the COVID-19 pandemic. The Ministry of Health program in Saudi Arabia aimed to cover 17.4 million adults (70% of the adult population of Saudi Arabia) by the third quarter of 2021. We investigated the impact of the COVID-19 vaccine on the clinical course and outcomes of the admitted confirmed COVID-19 patients, in comparison to non-vaccinated patients. Methodology A retrospective cross-sectional record review was conducted for all hospitalized confirmed COVID-19 patients at Dammam Medical Complex (Eastern Province, Saudi Arabia) from June to July 2021. Two groups were studied according to the vaccination status (i.e., vaccinated and non-vaccinated). Information regarding comorbidities, length of stay, high oxygen requirements, ICU admission, and mortality data were collected and analyzed using the Python programming language (version 3.7.6) with the use of SciPy library (1.4.1) and Statsmodels module (v0.11.1). Results The sample included a total of 260 admitted confirmed COVID-19 cases. The mortality was significantly lower in the vaccinated group versus the non-vaccinated group with an odds ratio (OR) of 0.378 (CI 0.154-0.928). In addition, the OR of ICU admission was 0.476 (CI 0.218-1.042) and OR of endotracheal intubation was 0.561 (CI 0.249-1.265), but these did not reach statistical significance. We also detected a statistically significant relationship between mortality - regardless of vaccination status - and age ≥ 65 years (P=0.000, OR=7.51; 95%CI 3.13 to 18.04), chronic kidney disease (P=0.010, OR=5.62; CI 1.52 to 20.79), and renal transplant (P=0.037, OR=10.17; CI 1.15 to 89.76). Of note, most of our vaccinated patients received only a single dose (85%). Conclusion There is a significant reduction in mortality cases as well as less complicated hospital courses among the vaccinated group, in spite of the fact that most of our admitted patients had only a single vaccine shot. Suboptimal response to the vaccines was observed in the elder, chronic kidney disease, and renal transplant patients, hence the poorer outcomes in comparison to other patients.